Frozen AC Coils & How to Fix Them

The refrigeration cycle for your HVAC system is a complex cycle with multiple different components that work together to cool your home. Among those components are two coils, the evaporator coil and the condenser coil, which work together to maintain the desired comfort level in your home. The evaporator coil is located inside your air handler or paired with your furnace, while the condenser coil is in the outdoor unit. Frozen coils are one of the most common faults that an HVAC company in Knoxville is likely to be called to fix. With that in mind, let's explore why the coils freeze and what can be done to fix it.

Warning Signs That Your Coils Are Frozen

There are a few warning signs that you might notice if your coils have frozen, although some are more obvious than others. If you have noticed any of these issues, it may be time to call an HVAC company in Knoxville to service your HVAC system. Some of the most common warning signs include the following:

• Heat Pump/AC is running but not cooling
• Heat Pump/AC is blowing warm air
• Visible ice on the evaporator coil
• Frozen refrigerant lines and visible ice on the outdoor unit
• Pooling water close to the indoor drain pan

Some of these can be indicators of other AC problems aside from frozen coils, so it is important to consult with an HVAC company in Knoxville to determine precisely where the issue lies.

Common Causes of Frozen Evaporator Coils

If your evaporator coil is frozen, it is likely to be down to one of these common causes:

1. Dirty Air Filters - When your air filter is dirty, it will begin to restrict airflow throughout the HVAC system, making it difficult to provide cool air; this can cause the evaporator to begin to freeze. To avoid this, you should change your air filters every 30 to 90 days.
2. Dirty Evaporator Coil - Dirty filters can also lead to a dirty evaporator coil, which is one of the most common causes of a frozen coil. Dirt, dust, and other debris can accumulate on the coil, acting as an insulator and restricting air circulation in the coil. Ask an HVAC company in Knoxville to clean the coil during your regular maintenance visits to avoid a build-up of dirt.
3. Blocked Return Vents - You may have noticed a common theme in that poor airflow in your HVAC system is often the cause of frozen coils. When a return vent is blocked, the flow of air over the evaporator coil will be inadequate. Make sure all of the return vents are clear of obstructions and debris. Often, a couch or other piece of furniture might block the vent. You may also want to contact an HVAC company in Knoxville about duct cleaning to have your return vents professionally cleaned.
4. Faulty/Broken Thermostat - When your thermostat is not functioning correctly, it can cause your evaporator coil to freeze. If you find that the coils seem to freeze overnight and thaw out during the day, it is a strong indication that the thermostat is the culprit, as it may not tell the HVAC unit to shut down as the temperature falls overnight.
5. Low or Leaking Refrigerant - If your HVAC unit has developed a refrigerant leak, the level will drop too low, and the HVAC will not be able to run as efficiently as it should. Check for any oily residue around the evaporator coil or a hissing sound coming from either the evaporator or condenser coil. Call an HVAC company in Knoxville immediately if you notice these signs.

What To Do If Your Coils Are Frozen To speed up thawing of a frozen evaporator coil, switch your thermostat fan setting to "On" instead of "Auto." The continuous airflow from the HVAC fan will help melt the ice on the coil, though it may take several hours. Alternatively, you can use a hair dryer on a low or medium setting, keeping it about six inches from the coil to avoid damage.

Never try to chip away at the ice, as this could harm the coil and lead to a refrigerant leak.

While waiting for the coil to defrost, call an HVAC company in Knoxville for emergency AC or heat pump repair. If temperatures are more relaxed, you may be able to wait a day or two for service. Just make sure the coil is fully thawed, and the air filter is replaced before restarting your system, as running it with a frozen coil can severely damage the condenser.

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Gent Heating and Cooling provide heating and air conditioning for residential and commercial clients in Knoxville, Knox County, and the surrounding East Tennessee area. Over 20 Years experience. Customer Service is Our Top Priority. We strive to be on time, provide accurate estimates, and have most replacement products on our service vehicles.

Call 865-213-3818 or email office@genthvac.com

www.gentheatandcool.com